Heart rate monitors are popular in fitness and other applications which require the monitors to have size and form factors which do not interfere with the activity of the user being monitored. Unfortunately devices which measure heart rate presently require electrodes on multiple parts of the body, or a location near the heart on the chest, and are cumbersome, especially for women. Furthermore, heart rate signals on the arm are extremely small and require amplification, and the amplifiers may be easily saturated by interference components such as muscle movement, 60 Hz noise radiation from lighting or other equipment, respiration, electrode connection and disconnection during activity, baseline wander, or other sources of interference.
Thus, there exists a need for an improved heart rate monitor that can detect and distinguish a heartbeat from an otherwise contaminated system with noise components potentially larger than the signal of interest (and/or in the same frequency band), and to create an amplification system which can eliminate these larger components so as not to saturate the monitoring device.